This disclosure relates generally to alignment systems for spherical-shaped objects, and more particularly, to an apparatus and method for manipulating and aligning spherical-shaped objects suitable for use in the manufacture and transport of spherical-shaped semiconductor integrated circuits.
Conventional integrated circuits, or "chips," normally require processing at multiple facilities, being manufactured as flat surface semiconductor wafers in a specialized manufacturing facility, and then transferred to a fabrication facility, where several layers are processed onto the wafer. The wafer is then cut into one or more chips and assembled into packages. The enormous effort and expense required for creating perfectly flat silicon wafers hampers the process of creating chips. High manufacturing costs make the chips expensive, for example, dust-free clean rooms and temperature-controlled manufacturing and storage areas are necessary to prevent the wafers and chips from warping. Moreover, the wafers typically have some defects in spite of all the precautions taken, due to the difficulty in making a large, single, highly pure crystal.
As the demand for smaller electronic devices continues, integrated circuits must become smaller, and the above-described wafer defects will become more significant. As such, alternatives to chips will play an increasingly important role in the future. For example, U.S. Pat. No. 5,955,776 discloses a method and apparatus for manufacturing a spherical-shaped semiconductor integrated circuit having many benefits over chips.
Spherical-shaped semiconductor fabrication includes a variety of processing steps, including deposition of films and photolithography, which require that the spherical-shaped semiconductor be correctly aligned. Alignment generally involves finding one or more alignment marks placed on a semiconductor before production, and then manipulating the semiconductor to align the mark correctly. This process is relatively simple with a chip, which only has two readily discernable sides.
However, because of its spherical shape, the alignment mark of the spherical-shaped semiconductor can be in any number of orientations at the end of the manufacture stage, requiring more sophisticated alignment considerations. Moreover, physically rotating a spherical-shaped semiconductor for alignment is fraught with difficulties. First, the spherical-shaped semiconductor has a very small diameter. Second, physically grasping the spherical-shaped semiconductor may result in significant damage. Third, the spherical shape of the spherical-shaped semiconductor typically conceals at least one-half of its surface area from an optical sensing system.
Therefore, what is needed is an apparatus and method capable of readily aligning small spherical-shaped objects.